The present invention relates to a color adjusting method for an observed image from a laser scanning microscope, for example.
Fluorescence microscopes have been known as instruments used to observe a fluorescent image of an observed specimen. In the fluorescence microscope, a specimen to be observed is dyed beforehand with a fluorescent reagent that generates fluorescence when receiving light with a specific wavelength. Illumination light with the specific wavelength is introduced via an objective. The fluorescence generated at the specimen is observed with the naked eye via the objective. The observed image may be recorded by photography.
Since it is very difficult to meet exposure requirements for photographing a fluorescent image of the observed specimen in the best condition, it is difficult to obtain a good picture. Since the result of photographing is known only after development, a failure in the photography will be known later, if any. This worsens the working efficiency significantly.
To overcome this problem, instead of such a fluorescence microscope, use of a laser scanning microscope where illumination light has been replaced with laser light has been considered. Specifically, in the laser scanning microscope, a laser light serving as a point source is projected via an objective on a specimen, while being caused to scan the specimen in the direction of the x-axis and that of the y-axis. A sensor senses the florescence from the specimen via the objective and the optical system, and produces a two-dimensional luminance data. The two-dimensional distribution of the luminance data is displayed on an image output unit, such as a CRT monitor or a color printer, in such a manner that the two-dimensional distribution comes to correspond to the x-y scanning position. This visualizes the observed image and enables the user to look at it. Such a laser scanning microscope visualizes the observed image more easily and accurately than the aforementioned fluorescence microscope.
Laser scanning microscopes further include a confocal laser scanning microscope equipped with a confocal optical system which is capable of sensing only data on the surface in focus by providing with a stop with a diameter equal to or less than the diffraction limit of the illumination light or the light to be measured in a position conjugate to the specimen, obtaining data items on the surface in focus at each position on Z-axis, and thereby producing a three-dimensional image.
The laser scanning microscopes have been treated as sophisticated measuring instruments capable of measuring two-dimensional or three-dimensional fluorescence images with high sensitivity and high resolution. As electronic imaging technology, data processing technology, and multimedia technology have recently made rapid progress, they have begun to be used as means for observing a fluorescent specimen as ordinary fluorescence microscopes are.
As such a laser scanning microscope is used as means for observing a fluorescent specimen, accurate data on colors which has not been regarded as very important have come to be needed.
Since conventional laser scanning microscopes is configured to obtain luminance data of two-dimensional or three-dimensional fluorescence and is not capable of obtaining data on colors of fluorescence, they adopt a method of directly displaying the luminance data of fluorescence as the luminance data of image or displaying pseudo colors by applying a suitable color for each luminance level, thereby causing to be easy to distinguish the subtle differences in the density which have been difficult to distinguish visually. However, such a method is not enough to obtain accurate data on colors.
To bring the data as close to the fluorescence color of the observed object as possible, a method of reproducing color data on the observed specimen by manipulating the RGB three primary colors using a simple look-up table (LUT) has been considered. Specifically, to reproduce color data using such an LUT, a recommended value for each wavelength of fluorescence is set beforehand in the LUT and the color data is reproduced in accordance with the wavelength of fluorescence of the observed specimen. Furthermore, the RGB three primary colors are adjusted subtly so that the reproduced color data may be displayed in the form the operator wants.
With such a method, the hue looks differently from when the fluorescent specimen is observed with the naked eye, depending on the output unit for displaying the observed specimen. In most cases, the hue when the observed image is displayed on a CRT monitor differs from that when the observed image is printed on a color printer. To adjust the colors between those output units so that they may coincide with each other by manipulating the LUT of the RGB three primary colors each time a difference in hue has been found, a certain level of skill and complicated work are needed.
Among these color adjusting techniques, the generally used techniques have confronted the subject of how to reproduce the same color tone when the image on a CRT monitor is printed on a printer, especially how to improve the color reproduction. One method of solving the problem is a method of using software to do complex matrix computation, as disclosed in, for example, Jpn. Pat. Appln. KOKAI Publication No. 8-163387. Another method of solving the problem is a method of using a dedicated circuit to do the matrix computation, as disclosed in Jpn. Pat. Appln. KOKAI Publication No. 5-183789.
These methods have the following problems: since they target the color space transformation in a very wide color gamut like a television dealing with general images, doing complex calculations by software takes an extremely long time and the necessity of providing a complex dedicated circuit for each output unit with a different characteristic results in a rise in production cost.